1. Field of the Invention
The present invention relates to a secondary battery.
2. Description of the Related Art
A lithium ion secondary battery includes a core pack having a bare cell and a protection circuit module (hereinafter, referred to as a ‘PCM’).
The bare cell includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator, supplies electrical energy to electronic devices, and is charged and discharged repeatedly during its lifetime. The PCM protects the secondary battery from over-charge and over-current, and prevents the secondary battery from decreasing performance due to over-discharge.
The bare cell and the PCM are assembled into a battery pack in such a way that the PCM is positioned on a side or on an upper surface of the bare cell having electrode terminals. When the PCM is positioned at a side of the bare cell, the relative placement results in a more complicated packaging. The shape of the side of the bare cell, possible interference between the side of the bare cell and devices mounted on a lower surface of the PCM, and the manner in which the PCM is coupled to the bare cell all complicate the packaging.